Utility meters, including mechanical, electromechanical, and solid-state meters, are well known and have been used for many years to measure the consumption of resources such as water, gas and electricity. Water meters, for example, generate data indicative of the consumption of water, where such data is used for billing purposes. Initially, utility meters were mechanical devices. As electronic technology advanced, such technology become more common in utility meters to make them smaller, more accurate, more dependable, smarter and less expensive. The electronics are typically used in a part of the meter called the “register” (as it “registers” the amount of consumption). As such, the use of electromechanical (hybrid meters) and electronic meters has become more common. Indeed, most modern electricity meters, for example, are fully electronic meters (static meters).
Traditionally, meter reading personnel would periodically travel to each site where a utility meter was installed, inspect a meter installation and manually record the consumption data. The customer would then receive a bill based on such collected data. Today, modern meters are increasingly equipped with transmitters giving such meters Automatic Meter Reading (AMR) capabilities. Such technology allows utility meters to automatically communicate consumption data to a remote receiver and the remote receiver transfers the data to a “system owner” (e.g. Utility Provider). Such transmitters are either electrically associated with the meter's register or designed into (integral to) the meter's register.
Notably, for at least safety reasons, water meters (and their associated electronic features) do not have access to a power grid (such as a typical residential power gird that powers homes) requiring such meters to be powered by power sources that can be depleted over time (e.g. a battery). Therefore, the meter and associated AMR technology is designed for minimal power consumption so that such technology may be powered for extended periods of time (e.g. 10 years) by power sources such as batteries.
Another challenge to the manufacturers of utility meters and ARM systems, in general, is that the utility meter market is very cost sensitive. A water utility, for example, may need to purchase 100,000 fluid meters (with associated AMR features) and the savings accumulate quickly as costs are reduced. A one-dollar cost reduction for an AMR transmitter quickly becomes a $100,000 savings. Further, dependability is a critical factor. Thus, for water meters, an AMR system is expected to operate adequately for at least 10 years at the lowest possible design costs while being powered by a battery.
Initially, water utilities had meter readers drive out to each water meter, read the meter, and manually record the consumption data. A very large and expensive task for a utility with 100,000 meters and there is likely to be errors in the manually recorded data for 100,000 meters.
The first AMR systems simplified such task by associating a short-range transmitter with the meter register and giving the meter reader a receiver he/she carried so that the meter reader would simply walk by the utility meter and the data would be automatically transmitted to the receiver associated with the meter reader. Nice improvement but such still required the meter reader to walk close by each meter. As transmitter technology improved, drive-by systems were developed where the receiver was associated with a vehicle and the meter reader simply drove down the street. Such systems are still in wide use today.
One “weakness” of walk-by and drive-by systems is that real time data or near real time data is not possible. One cannot typically access consumption data any time desired. However, consumers and utilities wanted such capability. Thus, fixed-network systems were developed. In a fixed-network system “remote receives” (perhaps called “Collectors”) are placed at various locations throughout the utility's customer areas. Such collectors had access to adequate power so that they could stay on all the time. Further, such collectors had a communication path to the utility. Additionally, the water meter transmitter would include a receiver and listen for a request for data. Thus, a particular water meter transmitter could be accessed whenever the utility desired.
There is always a price to pay for improved performance and the price for real time data is money. The system cost more, the meter transmitter cost more, the system is more complex, and thus, more prone to failures. That said, it should be appreciated that all of the above described AMR systems have their trade-offs between equipment costs, battery cost, battery life, transmission frequency (how often they transmit) and transmission distance and whether or not they can provide real or near real time data.
Notably, not all utility providers have the same amount of funds to purchase metering technology. Some utilities are required to purchase lower cost walk-by and drive-by systems until they can afford to migrate to a fixed network system. Some utilities may have large and very diverse coverage areas requiring fixed network in one area, drive-by technology in another area and walk-by technology in yet another area. Unfortunately, there was a problem with prior art systems in that prior art drive-by/walk-by and Fixed network AMR systems were not compatible with each other. Restated, prior art drive-by/walk-by transmitters were not configured to operate in fixed network systems and vice-versa. For example, a typical drive-by/walk-by system transmitter may transmit a 0.08 Watt data (a “whisper”) signal while a typical fixed network transmitter may operate at up to 1.0 watts (a “shout”). Additionally, it should be appreciated that for a two-way communication system the water meter transmitter has a receiver AND a transmitter—sometimes called a “transceiver”. Further, if a first transceiver (T1) transmits an “X-watt” signal to a second transceiver (T2), transceiver T2 should transmit an X-watt response signal. To use an analogy, if person A whispers to person B, person B should whisper back to person A, not shout back. If you whisper to someone that had to shout to you that someone is unlikely to hear you. Same for radio signals.
Such incapability between walk-by/drive-by/fixed network systems presented a huge problem to water utilities. The technology that provides the above described advantages is not free and utilities must be careful to select the best AMR system for their needs. Additionally, while a fixed network system may clearly the best technical solution for a particular area, a utility may not have the funds to install a fixed network solution. Thus, such a utility may simply purchase a system it can afford such as a less expensive walk-by/drive-by system. When the above described utility decides to upgrade to a fixed network solution as funds become available, it must replace the drive-by transmitters with RF systems suitable for a fixed network. To do so perfectly good transmitters were scrapped for updated transmitters. Such an upgrade process is clearly a waste of resources as perfectly good meter transmitters are scrapped.
Back at least as early as 2004 MARS® Water was the first company to develop and patent the “universal transmitter” particularly useful for water meters. Such Universal Meter Transmitter (UMT) is disclosed in commonly owned U.S. Pat. No. 7,498,953, filed 16 Nov. 2004, U.S. Pat. No. 7,994,935, U.S. Pat. No. 8,610,594, and recently allowed patent application Ser. No. 14/108,314, the contents of which are incorporated herein by this reference for all that they disclose for all purposes. Such a universal meter transmitter (UMT) is configured to be associated with a water meter and is configurable to operate in any one of a plurality of modes (such as a walk-by, drive-by and a Fixed Network mode) without hardware modification with some embodiments including auto-calibration routines to configure the AMR network. With such an UMT device, a water utility may first implement a walk-by/drive-by AMR system and then migrate/upgrade to a fixed network solution at minimal costs as the transmitter can be used in the new system.
MARS′® innovation efforts continue as the disclosed technology relates to an improved AMR system comprising UMT transmitters that combine the best features from walk-by systems and fixed network systems as described below.
One point to consider about all the various AMR systems identified above is that for all such systems there are typically many, many more Meter Transmitters than Remote Receivers (perhaps 50,000 meter transmitters to 1 remote receiver). Restated, every utility meter does not have its own dedicated meter reader. Indeed, there may only be one meter reader for 50,000 meters. Thus, the most cost effective and competitive system is one that transfers costs from the meter transmitter to the Remote Receiver (meter reader).
Embodiments of the disclosed technology leverage the concept of transferring costs from the meter transmitter to the remote receiver. For some UMTS, the most expensive component is the battery. Reducing battery costs for the UMT is a huge advantage. The most power hungry activity of a typical AMR system is transmitting a data signal to a remote location. Thus, the lower the power level needed to transmit a signal the longer a particular battery style will last. Alternatively, instead of extending battery life a lower cost battery may be used (or a combination of both).
To better appreciate transmitter power levels and how the environment affects the transmitted data signal from an UMT to a Remote Receiver a review of the environmental factors that attenuate Radio Frequency (RF) signals along its propagation path is useful. The environmental issues with RF propagation include:
(a) Scattering: Signal scattering can be caused by a random arrangement of signal wavelength sized (or smaller) objects (about 12-13 inches for the typical AMR frequency). Rain is a good example. An analogy would be shining a light through fog as opposed to clear air.
(b) Absorption/Reflection: When RF energy passes through a non-RF transparent structure some of its energy is absorbed and/or reflected. Luckily the frequency of the transmitted signal does not change but amplitude is attenuated when absorbed and at least redirected when reflected. An “RF Transparent” structure is simply an object that has no significant reflection or absorption of RF signals (similar to the way glass is light transparent).
(c) Diffraction: Diffraction is simply a special type of “reflection” caused by abrupt changes and sharp non-RF transparent surface “edges” which causes signal distortion.
(e) Distance: Even in perfect “free space” line-of-site conditions with no obstructions, as radio waves travel the signal (and associated energy) is distributed/divided over an increasingly wider area, and thus, becomes weaker (like putting a drop of food coloring in water—as it disperses over a wider area the color gets “weaker”). Consequently, the amount of detectable radiation varies inversely as the square of the distance from an emitting object. Simply put, as radiation (e.g. radio waves) moves away from its source it is steadily diluted as it spreads over a progressively larger surface area.
Based on the above, the RF environmental propagation parameters that need to be considered include scattering, absorption/reflection, diffraction, and distance. Notably, for a fixed (non-moving) Universal Meter Transmitter (UMT), substantially all such propagation parameters are basically a function of remote receiver antenna height and distance relative to the UMT. The goal is to achieve the best propagation path between UMT and remote receiver. The best propagation path between the UMT and a remote receiver is a line-of-sight path. A line-of-sight path is exactly what it sounds like . . . a “straight path” where there is nothing between the receiver and the UMT but air and where the distance between the UMT and the remote receiver is minimized.
Notably, the UMTS are installed in a water meter pit below ground level and they do not move. Thus, what is needed is a “Remote Receiver” that can move to achieve a line-of-sight propagation path between a stationary UMT and the Remote Receiver and minimize the distance between same. Walk-by and Drive-by systems do such to a certain extent, but such systems do not maximize the process. What is needed is a system that leverages the low power benefits of walk-by and drive-by systems while providing real time or near real time data services while transferring technology costs from the UMT to the remote receiver.
The disclosed technology achieves the most cost-effective ARM system comprising a Universal Meter Transmitter (UMT) that operates in a plurality of modes such as the walk-by, drive-by, and fixed network modes as well as a new “fly-by” mode disclosed in this document without the need for hardware changes. For the disclosed fly-by modes, the receiver is preferably associated with a hybrid lighter than air technology (e.g. blimp) and electric powered drone system. The “blimp” does the heavy lifting and the drone technology handles the maneuvering to address the above described RF propagation path issues. One such drone system is simply a drone that flies straight up (Drone Tower™) when collecting data and then returns to its base. Another drone-based system is a hybrid between a drive-by and fixed network that creates a new “Fly-By” mode.
It should be appreciated that the disclosed drone-based system allows the Meter Transmitter to transmit at a lower power level which allows a manufacture to configure the UMT to transmit at a lower power thereby prolonging battery life and/or allowing the use of lower cost batteries while improving data collection efficiency while also transferring costs from the Meter Transmitter to the Remote Receiver.